Orphanin FQ/nociceptin in the ventromedial nucleus facilitates lordosis in female rats.
The localization of opioid receptor-like (ORL-1) orphan receptor in the ventromedial nucleus of the hypothalamus (VMH) suggested a role for this opioid system in the regulation of lordosis behavior. Recently, the ligand for ORL-1, orphanin FQ/nociceptin (OFQ/N), has been characterized and also demonstrated to be present in the VMH. The present experiments examined whether OFQ/N in the VMH facilitates lordosis behavior in estrogen-primed, sexually unreceptive female rats, and whether estrogen regulates ORL-1 levels in the VMH. Estrogen was shown to increase ORL-1 immunoreactivity in the VMH, and microinfusions of OFQ/N into the VMH facilitated lordosis behavior in a dose-dependent manner.
Sinchak
K
K
Department of Neurobiology, Mental Retardation Research Center, Brain Research Institute, UCLA School of Medicine, Los Angeles, California 90095-1763, USA.
Hendricks
D G
DG
Baroudi
R
R
Micevych
P E
PE
D000595:Amino Acid Sequence; D000818:Animals; D004958:Estradiol / Q000494:pharmacology; D005260:Female; D007033:Hypothalamus, Middle / Q000737:chemistry / Q000187:drug effects / Q000502:physiology*; D007150:Immunohistochemistry; D008297:Male; D008969:Molecular Sequence Data; D018847:Opioid Peptides / Q000032:analysis / Q000502:physiology*; D010052:Ovariectomy; D010053:Ovary / Q000502:physiology; D011187:Posture / Q000502:physiology*; D051381:Rats; D011957:Receptors, Opioid / Q000819:agonists*; D012726:Sexual Behavior, Animal / Q000502:physiology*; D000097629:Nociceptin
D004958:Estradiol; D018847:Opioid Peptides; D011957:Receptors, Opioid; D000097629:Nociceptin